1. Field of the Invention
The invention relates to an air guiding device that has a spoiler lip and that is mountable on a front part of a motor vehicle via an adapter. A pneumatic actuating device shifts the spoiler lip between a retracted rest position and an extended position.
2. Description of the Related Art
US 2003/0116996 and US 2005/0012359 disclose spoiler devices that have a spoiler lip extending in the transverse direction of the vehicle at the front of the vehicle. The spoiler lip is made of an elastomer and a pneumatic actuating device moves the spoiler lip between a retracted rest position and an extended maximum position to optimize an aerodynamic effect with respect to output values of the motor vehicle. The pneumatic actuating device of the air guiding device known from the prior art comprises a pneumatic actuator with chambers that can be filled or emptied to transfer the spoiler lip between the retracted rest position and the extended maximum position. The elastomer of the spoiler lip is deformed elastically during the filling operation, thus building up a restoring force, which, during the emptying operation, returns the spoiler lip back in the direction of the rest position again.
In the cold, elastomers from which the spoiler lip can be manufactured have increased hysteresis values that make it difficult for the spoiler lip to return automatically in the direction of the rest position. Furthermore, in the cold, the relaxation properties of the elastomers change, and therefore, if the spoiler lip were extended for a prolonged period in the cold, the spoiler lip would require a prolonged period to be able to be transferred again from the extended position into the retracted rest position. This cold retraction behavior of the spoiler lip is disadvantageous.
It is the object of the present invention to provide a novel air guiding device for a motor vehicle.